Nobody killed Pluto.

Back in the early 1800s children used to memorize the names of the 12 planets: Mercury, Venus, Earth, Ceres, Pallas, Juno, Vesta, Mars, Jupiter, Saturn, Uranus, and Neptune. But then in 1845 astronomers discovered Astraea, and now there were 13. In 1847 three more were discovered: Hebe, Iris, and Flora. Then Metis, Hygiea, Parthenope, and Victoria by 1850. The 100th asteroid was discovered in 1868, and the pace only got quicker from there. Somewhere along that line people started using the words “asteroid” and “asteroid belt” and schoolchildren were mercifully spared the pointless task of memorizing hundreds, and later many thousands, of names of asteroids.

The same thing happened to Pluto. Just as Ceres was the first discovered asteroid, Pluto was the first discovered TNO. There are now hundreds of named TNO and thousands more that are just numbered. Nobody should force schoolchildren to memorize them all. Just tell them that there are an unknown number of objects in the Kuiper belt and the Oort cloud and they’ll know as much as they need to know. Give them bonus points if they know the names Ceres and Pluto, and more if they know why these two were discovered first of all the objects in their class: they’re the biggest. Otherwise there’s nothing special about them.

> Nobody should force schoolchildren to memorize them all. Just tell them that there are an unknown number of objects in the Kuiper belt and the Oort cloud and they’ll know as much as they need to know.

Or just tell them that there's an unknown number of planets in the solar system, but the big 8 are the only ones they're expected to memorize. That was actually the original plan by the IAU, and how many (I believe most) planetary scientists define planet today.

The decision being based mainly on not wanting to add newly discovered planets to the list of planets in the solar system always rubbed me the wrong way. As is the tendency for people to mistakenly believe that this is settled science, when it's actually an unsettled nomenclature debate.

I thought that there were only four planets? Jupiter, Saturn, Uranus, Neptune

I think he’s referring to Mike Brown’s book “How I Killed Pluto and Why It Had It Coming”. It’s a great read.

I didn't know he wrote a book. I was referring to his handle "@plutokiller.com" on Bluesky.

Yea, good book. But he’s wrong. Pluto is still there; nobody has killed it.

His team discovered Eris and many other trans-neptunian objects, which did fuel the discussion behind pluto's demotion: greatly increase the number of planets, or demote pluto? They're also behind the Planet 9 theory that's discussed in the article.